perf xtensa: Remove dwarf-regs.c

The file just provides the function get_arch_regstr, however, if in
the only caller get_dwarf_regstr EM_HOST is used for the EM_NONE case
the function can never be called. So remove as dead code. As this is
the only file in the arch/xtensa/util clean up Build files. Tidy up the
EM_NONE cases for xtensa in dwarf-regs.c.

Reviewed-by: Masami Hiramatsu (Google) <[e-mail]>
Signed-off-by: Ian Rogers <[e-mail]>
Cc: Anup Patel <[e-mail]>
Cc: Yang Jihong <[e-mail]>
Cc: Palmer Dabbelt <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Albert Ou <[e-mail]>
Cc: Shenlin Liang <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Guilherme Amadio <[e-mail]>
Cc: Steinar H. Gunderson <[e-mail]>
Cc: Changbin Du <[e-mail]>
Cc: Alexander Lobakin <[e-mail]>
Cc: Przemek Kitszel <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Guo Ren <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Mike Leach <[e-mail]>
Cc: Chen Pei <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Oliver Upton <[e-mail]>
Cc: Aditya Gupta <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: Bibo Mao <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Atish Patra <[e-mail]>
Cc: Dima Kogan <[e-mail]>
Cc: Paul Walmsley <[e-mail]>
Cc: Dr. David Alan Gilbert <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/arch/xtensa/Build

···
-perf-util-y += util/

tools/perf/arch/xtensa/util/Build

···
-perf-$(CONFIG_LIBDW) += dwarf-regs.o

tools/perf/arch/xtensa/util/dwarf-regs.c

···
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Mapping of DWARF debug register numbers into register names.
- *
- * Copyright (c) 2015 Cadence Design Systems Inc.
- */
-
-#include <stddef.h>
-#include <dwarf-regs.h>
-
-#define XTENSA_MAX_REGS 16
-
-const char *xtensa_regs_table[XTENSA_MAX_REGS] = {
-	"a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7",
-	"a8", "a9", "a10", "a11", "a12", "a13", "a14", "a15",
-};
-
-const char *get_arch_regstr(unsigned int n)
-{
-	return n < XTENSA_MAX_REGS ? xtensa_regs_table[n] : NULL;
-}

tools/perf/util/dwarf-regs.c

···
 #if EM_HOST == EM_X86_64 || EM_HOST == EM_386 || EM_HOST == EM_AARCH64 || EM_HOST == EM_ARM \
     || EM_HOST == EM_CSKY || EM_HOST == EM_LOONGARCH || EM_HOST == EM_MIPS || EM_HOST == EM_PPC \
     || EM_HOST == EM_PPC64 || EM_HOST == EM_RISCV || EM_HOST == EM_S390 || EM_HOST == EM_SH \
-    || EM_HOST == EM_SPARC || EM_HOST == EM_SPARCV9
+    || EM_HOST == EM_SPARC || EM_HOST == EM_SPARCV9 || EM_HOST == EM_XTENSA
 	if (machine == EM_NONE) {
 		/* Generic arch - use host arch */
 		machine = EM_HOST;
···
 #if EM_HOST != EM_X86_64 && EM_HOST != EM_386 && EM_HOST != EM_AARCH64 && EM_HOST != EM_ARM \
     && EM_HOST != EM_CSKY && EM_HOST != EM_LOONGARCH && EM_HOST != EM_MIPS && EM_HOST != EM_PPC \
     && EM_HOST != EM_PPC64 && EM_HOST != EM_RISCV && EM_HOST != EM_S390 && EM_HOST != EM_SH \
-    && EM_HOST != EM_SPARC && EM_HOST != EM_SPARCV9
+    && EM_HOST != EM_SPARC && EM_HOST != EM_SPARCV9 && EM_HOST != EM_XTENSA
 	case EM_NONE:	/* Generic arch - use host arch */
 		return get_arch_regstr(n);
 #endif

tools/perf/util/include/dwarf-regs.h

···
 #if !defined(__x86_64__) && !defined(__i386__) && !defined(__aarch64__) && !defined(__arm__) \
     && !defined(__loongarch__) && !defined(__mips__) && !defined(__powerpc__) \
     && !defined(__powerpc64__) && !defined(__riscv__) && !defined(__s390x__) && !defined(__sh__) \
-    && !defined(__sparc64__) && !defined(__sparc__)
+    && !defined(__sparc64__) && !defined(__sparc__) && !defined(__xtensa__)
 const char *get_arch_regstr(unsigned int n);
 #endif